And welcome from me as well just back from another meeting of the Potent Voyager team still doing the tortoise thing but we are now have a couple more diagrams to add to the patent application that we really do hope to get finished this year. Is Grape Juice planning to use traditional rocketry to attempt the prize or something more exotic Anyway best of luck I am enough of a space enthusiast to hope someone wins this prize even if it is not my team(tho I do think/hope we will be capable of achieving the tasks specifications eventually)

Someone has to tilt at windmills.So that we know what to do when the real giants come!!!!

Hey Awesome, Thank you guys so much for the welcome's! I'm glad to be here! =D(I'm the sole member of Grape Juice)

pauldear:Thank you!

Jay:Thanks! Simple really, I'm not much of a coffee or beer drinker, and pop can be expensive. so I often drink juice when I'm programming. so for one of my programs I used 'Grape juice' as a project name, since it was right beside me. and the name just kind of stuck.

SANEAlex:Thank you aswell!Glad to see there are more people still active, looking around the forum/web it looked like most of the interest had died off. I hope you guys get approved for the patent(s)Innovation is always good

and I'm going for something a bit more exotic, though I have 2 idea's bouncing around in my head, here's a summary:

1) air/vacuum cannon using the pressure of the ocean through ~km long tube with a kink in it (I'll explain the kink in a later post) wich should bring it up to (at least) mach 2-5. without using any on board fuel, after which I plan to use a hybrid engine to bring it up to mach 20-25 and enter orbit. fairly simple in principle, but will need a boat load of math (I've mainly just scratch built model airplanes that focused on slow+lots of lift for rubber power, so this is way outside my experience zone but I feel confident I can calculate it, and if the numbers look promising then I'll build it)

2) Orbital airship, I thought I was the first to come up with this Idea, but when I started doing some crude research I found that it's a real thing, and JP Aerospace's design is eerily similar to what I had in mind. and what I had in mind:Delta shape, Hydrogen filled + partial vacuum and instead letting the internal gas expand, I'll just increase the vacuum as I go up.and I would use 3 solar powered ion thrusters for thrust.I'll give further details in another post. my biggest issue with this is weight (power conversion for ion thrusters) + expense (leading wing edge I plan to use tungsten to deal with the hypersonic friction heat), so I might use this Idea for when I attempt the Lunar X challenge instead, unless i find out to make this feasible for cheap. then I'll try doing both challenges at once :p

anyways, I have a lot of math to do, so hopefully in a few days I'll make a larger post with diagrams + pictures describing my thoughts/Idea's.

As it is along the lines of using sea pressure to contain a hydrogen cannon blast i am not sure how far along with the idea as i don't recall anything posted about it recently but the link may give you some help looking for people who may have data useful for you idea if it does share some simile aspects.

Ps for Paul if you are also reading this I still don't seem to get notifications by email from the site that changes have happened to a thread.Edited to add i have just checked the settings and it seems that unlike other forums running on the same software you are not automaticly added as being subscribed to a thread when you post to it here you have to manually tick the subscribe button for each subfora i have now added this one and a few others and hopefully that will fix the problem i will let you all know if it does or doesn't if there is a reply on this thread.

Someone has to tilt at windmills.So that we know what to do when the real giants come!!!!

You mentioned you would be explaining the 'kink' in your tube. From your description, I'm assuming you are placing the tube under a vacuum and then applying pressure behind your payload; at least that seems the logical approach. The cover could always just be loosely placed on the end held by the vacuum and when the projectile came close, even with a good vacuum pulled in such a long tube, the pressure ahead of the projectile might be enough to blow it aside before getting hit by your payload. Reminds me of a ocean water power generation project I read about that was done off Cuba; it pumped cold water from a tube extending thousands of feet deep to cold water where it was pumped to the surface and acted with the warm surface water to create a low pressure turbine system. I believed they also tried it in the US off the Hawaiian coast. Different purposes than what you want to do but none the less, if your cannon launcher doesn't work, convert it to a power generator.

Differs from John Hunter's cannon. I have some questions for his approach. He says an iris will close after the launching to 'save the hydrogen gas'. Seems hydrogen would be an inexpensive commodity in such a project. Also, he doesn't say anything about evacuating his cannon before firing. If he expects the half ton 'payload' projectile to be moving at 13,000 mph when it exits the cannon, that would build up a lot of pressure in from of the projectile, especially in already increased air pressure 1,600' below sea level. I would also be interested in how he plans to lube a 13,000mph 1/2 ton projectile in a 3,300' long 'barrel'. I suppose if I could raise $500 million dollars I would play with the idea.

microsat wrote:The cover could always just be loosely placed on the end held by the vacuum and when the projectile came close, even with a good vacuum pulled in such a long tube, the pressure ahead of the projectile might be enough to blow it aside before getting hit by your payload.

Small plasma windows have successfully maintained vacuum pressure against atmospheric. Making a large one that can do the same would be a major engineering challenge in itself though. The reward would be that the “cover” could be switched on and off instantly. Otherwise, a well designed sliding slotted shutter should be much simpler than an iris.

Project High Altitude Research Program (Project HARP) was on the verge of launching cannon-fired rockets to orbit when the plug was pulled on the program. Their largest guns were “only” 120 feet (36.4 meters). A mylar sheet was all that was needed to seal the 16-inch (406 mm) muzzle so the barrel could be evacuated. Evacuation added only 150 feet per second (46 m.p.s.) to the muzzle velocity, which was nominally 6100 feet per second (1860 m.p.s.), but that small difference increased the apogee by 20,000 feet (6096 meters).

Jay wrote: Small plasma windows have successfully maintained vacuum pressure against atmospheric. Making a large one that can do the same would be a major engineering challenge in itself though. The reward would be that the “cover” could be switched on and off instantly. Otherwise, a well designed sliding slotted shutter should be much simpler than an iris.

Didn't know about the plasma seal for vacuums, good to know. In testing our experimental motors for ignition/re-ignition in space we built an 200mm vacuum chamber and simply use an aluminum plate with a silicon gasket. When the vacuum is applied, it holds the cap on yet when we do ignition, the cap blows away harmlessly. For pressure tests, we have used other materials (including mylar)as burst disks.

jay wrote: Project High Altitude Research Program (Project HARP) was on the verge of launching cannon-fired rockets to orbit when the plug was pulled on the program. Their largest guns were “only” 120 feet (36.4 meters). A mylar sheet was all that was needed to seal the 16-inch (406 mm) muzzle so the barrel could be evacuated. Evacuation added only 150 feet per second (46 m.p.s.) to the muzzle velocity, which was nominally 6100 feet per second (1860 m.p.s.), but that small difference increased the apogee by 20,000 feet (6096 meters).

If the ocean cannons are to be thousands of feet long, that difference in muzzle velocity would be greater. The idea of accelerating guns to lessen the G-force and increase the speed does have some interesting advantages for specific very small payloads. Something like a rail gun could deliver small things to sub-orbital and perhaps achieve orbit with inclusion of a rocket motor for circularizing the orbit. Perhaps a 'circular' rail gun might speed such an object up with low G-forces and be able to obtain orbit with a larger variety of payloads.